A seven year veteran of the New York Police Department (NYPD) was allegedly part of the biker party that beat up wealthy Manhattan executive Alexian Lien, 33, during a controversial highway brawl in New York and has been placed on modified duties pending an investigation.

Sources revealed to The New York Post that the unidentified off-duty undercover officer who claimed he did not take part in the Sept. 29 beatdown of Lien was shown to be pounding Lien's SUV with his fist during the furious attack.

The officer reportedly told investigators that he was unable to help Lien because he got to the scene at the tail-end of the beating. The officer has since been placed on modified duty and has turned in his gun and badge.

It was good samaritan and father of 10, Sergio Consuegra, who eventually stepped in to end the beating of the father in front of his wife and 2-year-old daughter while he was on his way to church.

"At that moment, nobody's stepping in," Consuegra recalled during an interview with ABC 7 about how he faced down the bikers who was furious that Lien had crushed the spine of biker Edwin Mieses Jr. and was trying to escape.

"I felt tense. I felt that God was with me there," said Consuegra. "I said stop it, let it go. And then somehow one of them moved started moving and I said yeah this is enough now."

"At that moment I said, oh I gotta do something, there's a family in danger here," Consuegra added, "And they're gonna get killed, nobody intervened in this situation and nobody stepping in."

NYPD Internal Affairs Bureau officials want to penalize the officer but the Post's sources say their hands are tied because the Manhattan district attorney's office recently dropped charges against 43-year-old Allen Edwards of Queens for punching the rear window of Lien's SUV during the controversial fracas.

Still, probers believe their hands are tied, sources said, because authorities have dropped charges against another biker, Allen Edwards, 43, of Queens, who allegedly punched the rear window of Alexian Lien's Range Rover before Lien was pummeled in front of his wife and 2-year-old daughter.

In dropping the charges against Edwards, Karen Friedman Agnifilo, chief of the Manhattan district attorney's Trials Division, had said: "Prematurely charging individuals with low-level crimes does not further the goals of the investigation and could weaken the cases we expect to bring against the perpetrators of serious crimes."

On Monday during a discussion on MSNBC's "Morning Joe" New York City Mayor Michael Bloomberg said: "I think we all, no matter what your job is, have an obligation to help one another…if you see somebody getting beaten up, you know, let's go jump in and stop the fight."